Unless it was the only way I could get an unDRMed e-book, I would rather NOT buy a bundle. All I would want would be the e-book and I would have to get rid of the the p-book. The question here would be, is the e-book considered a separate book or is it the same book? In other words, would I be able to legally keep the e-book and sell the p-book? It would depend on how the bundle is sold.

Is it technically legal to sell the pbook part of the bundle and keep the ebook? Perhaps not. In practice, will anyone care? What would single out the pbook copy as being part of the bundle? Who would know it had been?

Certainly, no one has tried hard to stamp out things like used book stores. Aside from it likely being impossible, the books were already bought at retail once and generated revenue. The publishers may wish the folks buying the used copy had bought a new one, but keeping folks from buying the used copy would more likely prevent purchase of a new one. Books we buy used are books we don't mind waiting for them to show up as used copies, and taking the chance that they won't.

But if all you want is the ebook, I'm not sure I see a point to buying the bundle, unless you know you can resell the pbook copy and recoup part of the purchase price.
______Dennis